The GWs from NSBH systems exhibit unique differences when compared to either binary neutron star (BNS) or BBH systems. Firstly, the tidal effects in the case of NSBH are not as pronounced compared to BNS systems as only one companion can evince tidal effects. This leads to an increase in difficulty measuring tidal effects. Secondly, NSBH systems can go to very high mass ratios \(m_\mathrm {BH}/m_\mathrm {NS}\)  as the BH mass is not bounded, unlike BNS systems. With high mass ratio the tidal effects in NSBH systems become uninformative as the NS will plunge into the BH before having any substantial effect on the waveform [1]}. For systems where the BH is only slowly spinning and has a substantially larger mass than the NS, the GW signal resembles a BBH system with same masses [2]}. This was the case for GW190814 [3]}. In this event a \(23.2^{+1.1}_{-1.0}~M_\odot \)  BH coalesced with a \(2.59^{+0.08}_{-0.09}~M_\odot \)  compact object, whose nature is unknown. It could be either the heaviest NS or the lightest BH observed in a compact binary system. Lastly, for NSBH systems where the companions are of similar masses or the BH has high positive spin, finite size effects cause a dephasing of the waveform relative to a BBH with same masses and spins while tidal forces on the NS affect the amplitude of the waveform [4]}, [5]}. Depending on its equation of state, the NS can be entirely torn apart in a tidal disruption event [6]}, [7]}, [8]}. Such an event can be accompanied by the formation of a torus remnant around the BH [9]}, [10]} and a kilonova [11]}, [12]}, if the tidal disruption happens before the innermost stable circular orbit (ISCO). Then also the GW signal is highly affected, the amplitude of the merger is heavily suppressed and the ringdown part is missing completely [13]}, [14]}. As the tidal disruption event can only happen for NSBH systems it would be a smoking gun evidence for a NSBH binary. However, it should be noted that the disruption frequency will be in the frequency range of a few kHz where the detectors' sensitivity is not optimal [1]}, [16]}. The scenario of tidal disruption is not only the best case for the unambiguous identification of NSBH system but also can lead to potential electromagnetic counterparts [11]}, [18]}, [19]}, [20]}. In this work we motivate the use of gravitational-wave memory as a complementary resource for identifying the tidal disruption scenario which will help in distinguishing NSBH from BBH mergers.
